To rename your Lightroom catalog, locate the catalog and quit Lightroom. If you don’t know where your catalog is, the default Lightroom catalog is stored:
Mac (user) /Pictures / Lightroom
Win (user) / My Pictures / Lightroom
If you have made a new catalog, the easiest way to find it is to select Lightroom > Catalog Settings (Mac) / Edit > Catalog Settings (Win), and click General. Lightroom displays the path to the currently open catalog. Click the “Show” button to reveal the catalog in the Finder (Mac) / Explorer (Win).
There are three files that you need to rename. They are:
(your catalog name).lrcat
(your catalog name) Previews.lrdata
(your catalog name) Smart Previews.lrdata
Make sure that you leave the space between the catalog name and the word Previews in the two .lrdata files.
Note: If you have no smart previews in your catalog, you might not have the (your catalog name) Smart Previews.lrdata file.